The increase in the cost of the high-grade wood used for baseball and softball bats has resulted in an increase in the expense of breaking a ball bat. Also, an increase in the use of lower grade materials has resulted in bats breaking with greater frequency, and a corresponding greater cost.
As a result of the cost of high-grade materials and the quality problems associated with less expensive materials, several alternative baseball bat structures have been developed. A well-known alternative is to use metal in a ball bat's construction. This has several problems, including particularly the increasing costs of such metal bats and the prohibition against such bats by Major League Baseball.
A lesser-known alternative is to use a laminated wood construction. While this construction is advantageous for strength and other reasons, the problem of ball bat breakage has still not been solved.
The failure mode by which baseball bats break is not fully understood. However, it is clear that the point of impact with the ball, typically on the barrel of the bat, is not the likely location of the break. The most common location at which a baseball bat will break is in or near the handle portion, in a location where the bat is relatively small in diameter.
Upon impact with a ball, a baseball bat will vibrate. It is thought that, under typical strenuous conditions, the bat will momentarily assume a shape that is very slightly sinusoidal. Typically, there will be two nodes along the length of the bat, between which the bat will be deformed for a short period to a greater or lesser degree. Many factors may determine the amplitude and frequency of the vibration, including the structure of the bat, the grip strength and location by the player, the point of impact of the ball and the speed and direction of the ball and bat.
If the impact of the ball is sufficiently forceful, and various of the above factors combine unfavorably, the bat will break. Due to a combination of the forces involved and the strength characteristics of most bats, the location of the break is almost invariably at a location between the nodes, in the handle or in the area of transition between the handle and the barrel.
For the foregoing reasons, there is still a need for a baseball bat design that can reduce construction costs and at the same time reduce the frequency of broken bats. The improved bat design must include a reinforcing structure which reduces the incidence of breakage, particularly in the critical stress area where most breakage occurs.